Parathyroid adenoma

This article will help you read and understand your pathology report for parathyroid adenoma.\

by Archan Kakadekar MD and Jason K Wasserman MD PhD FRCPC, reviewed by our Patient Partners on December 8, 2020

parathyroid adenoma

Quick facts: 

  • Parathyroid adenoma is a common non-cancerous type of tumour that starts from cells normally found in one of the four parathyroid glands.
  • The parathyroid glands are located in the front of the neck close to the thyroid gland.
  • The parathyroid glands produce parathyroid hormone which helps control the amount of calcium in your blood.
  • Parathyroid adenomas produce extra parathyroid hormone (hyperparathyroidism) which can lead to increased calcium levels in the blood (hypercalcemia).

The function and anatomy of the parathyroid glands

 The parathyroid glands are part of the endocrine system which means they make hormones that travel around the body through the blood stream. Most people have four small parathyroid glands that are normally found in the front of the neck close to the much larger thyroid gland.

The parathyroid glands are made up of a combination of specialized cells called chief cells, oxyphil cells, and clear cells. These cells make parathyroid hormone (PTH) which is then released into the blood stream. Parathyroid hormone is important because it helps control the amount of calcium in your blood. Calcium is needed to maintain strong bones and to help your nervous system, muscles, and digestive system function normally.

What is a parathyroid adenoma?

A parathyroid adenoma is a benign (non-cancerous) tumour made up of cells normally found in the parathyroid gland. The tumour can be made up of one cell type or a combination of cell types. Unlike the normal parathyroid glands, a parathyroid adenoma may be large enough to be felt or seen in the front of the neck. Parathyroid adenomas are more common in women in the sixth and seventh decade of life.

parathyroid adenoma cells


Parathyroid adenomas often make extra parathyroid hormone which is then released into the blood. Doctors call this hyperparathyroidism. This leads to increased levels of calcium in the blood. Doctors call this hypercalcemia.

Symptoms of hypercalcemia include involuntary shaking (tremor), nausea, vomiting, abdominal pain, and confusion. Patients with prolonged hypercalcemia are also more likely to suffer from broken bones and kidney stones.

What causes a parathyroid adenoma?

Most parathyroid adenomas are sporadic which means doctors do not know what causes them. However, some genetic syndromes such as multiple endocrine neoplasia (MEN) and familial isolated hyperparathyroidism (FIHP), greatly increase a person’s risk for developing these tumours.

How do pathologists make this diagnosis?

Increased levels of parathyroid hormone or calcium in your blood are often the first signs of a parathyroid adenoma. Your doctor may also suspect the diagnosis if you have a lump in the front of your neck or symptoms related to increased blood calcium (see above).

Most doctors recommend surgery to remove the tumour. Once the tumour is removed the tissue sample is sent to a pathologist who examines it under the microscope. The diagnosis can usually be made by examining the a tissue sample stained with a combination of dyes called hematoxylin and eosin. However, some pathologists may perform an additional test called immunohistochemistry to confirm the diagnosis.

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